Thermostat



Jan. 5, 1937. W. A. RAY

THERMOSTAT Filed April 30, 1935 INVENTOR. Mam/v A. EA)

A TTORNEYS.

Patented Jan. 5, 1937 PATENT OFFICE THERMOSTAT William A. Bay, San Francisco, Calif., alaignor to General Controls Company, a corporation of California Application April 30, 1935, Serial No. 18,984

6Claims.

This invention relates to a thermostatic control device and more particularly to an improved construction for a domestic wall type thermostat.

It is an object of this invention to provide a thermostat of relatively high sensitivity and quick response. Present thermostats in domestic use often lag behind the room temperature by as much as This results in false room temperatures.

10 Another object of the invention is to provide a thermostat of a simplified and yet rugged construction. Domestic heating and its control are highly developed in a competitive way; articles for this use therefore; to succeed are required to be inexpensive as {well as rugged and simple.

The invention g'possesses other advantageous features and chic ts some of which, together with the foregoing, w 1 appear hereinafter wherein the present preferred form of my invention is so disclosed. In the drawing Figure 1 is a plan view of a thermostat embodying my invention.

Figure 2 is a section through the thermostat on the line 22 of Figure 3.

Figure 3 is a plan, partly in section, showing certain cons ructions in the thermostat.

Figures 4, 5 and 6 are respectively sections on the lines 4 55 and 6-5 of Figure 3.

In the construction illustrated I provide'a back H and a cage l2 fitting over the back II. The

back is fixed to a support as a wall as by wood screws l5. Screws it pass through the cage and engage nuts I4 to retain the cage in place.

It is a feature of this invention that the cage and back are made of a material having little if any heat capacity as well as being a poor heat conductor. This is desired to the end that the cage and back have as little efiect as is possible on the thermostat mechanism. I prefer to use Bakelite or some molded composition as the material,

jiroviding the cage with many apertures I6 so that free air circulation can take place through theme and over the mechanism therein.

The face of the cage is apertured and recessed to receive a flush metal plate I! upon which a thermometer I8 is mounted. The plate, being metal and being supported on a poor conductor, is heated and cooled quickly so that thermometer i8 represents accurately and without any undue delay the temperature of the room.

The thermostatic element comprises a bimetal strip 2!. A member 22 is riveted to strip 2|, an insulating strip 23 being placed between the two to cut down heat transmission from member 22 to said strip. One or more contacts 24 are carried by the member 22. The contact 24 cooperates with a fixed contact 28. This contact 26 is screwed into spool 30 and is connected by connector 21 to screw 28. This screw has a pin extension 29 slipping into receptacle connector 3|.

To adjust the travel of the bimetai strip I 5 'provide adjusting screw 32 on insulating strip 33 mounted between screw 28 and screw 44. A horseshoe magnet 36 is secured by strip 31 and screw 38 adjacent member 22 which is made of a magnetizable material. This combination in- 10 sures that the strip 2! will not move contact 24 until it can do so positively, the magnet holding the member 22 until the strip 2| acquires suflicient bias to snap the contacts together or apart. To facilitate the work of the magnet, member 22 is 15 apertured as at 39, providing parallel but separate magnetic paths.

To adjust the operating temperature of the bim'etal strip 2| I provide means for varying the position thereof. I rivet the strip 2| on an ex- 20 tending portion 4| of a member 42. A member 43 is bolted to the cage and has arms 45 extendmg therefrom to receive arms 44 on member 42. Th arms cooperate to form guides during oscillat on of member 42 about pin 46 which extends 25 through members 42 and 43.

A spring 41 urges member 42 in clockwise direction about pin 46.

Temperature scale knob BI is secured on stud 52 which is threaded through a nut 53 in memso her 43 and bears against member 42 to rock it about pin 46. The flange 54 of the knob ii is calibrated in degrees corresponding to the temperature at which the strip is responsive for a given setting with relation to indicia 55.

An "on and oil! switch is usually provided in conjunction with the device. In the form shown, an insulated arm 56 is mounted for rotation on nut 53. This arm carries a spring contact 51 which selectively engages contact 58 on insulated connector 59. This connector extends to terminal 6i.

While the use of a fixed magnet in a thermostat is not broadly new (see Massa, Patent 1,146,637), in the present structure achieves certain novel results. For example, I provide apertures-in the member-as well as the U channel. The apertures reduce heat transmission to the bimetal if the contacts heat from sparking while the U channel acts as an armature for the magnet. This materially simplifies construction.

The foregoing is a disclosure of the present preferred construction of my invention. It is to be understood that variations can be made therein without departing from my invention within the scope oi the claims.

I claim:

1. In a thermostat, a bimetal strip, a contact, a magnetizable member carrying said contact and attached to one end of said strip and continuing beyond said strip, said member being deformed to include as an armature a. U portion with the base of said U portion substantially parallel to the remainder of said member but projecting from said member toward a permanent magnet, and a permanent magnet adjacent to and cooperating with the base of the U in said U section as said armature.

2. En a thermostat, a bimetal strip, a magnetizable member attached to one end of said strip and continuing beyond said strip, and a contact carried by said member, said memher being apertured between said contact and said strip to provide a plurality of narrow arms to reduce materially the mass of metal Joining said contact and said strip to prevent substantially contact heat from affecting said strip.

3. In a thermostat, a bimetal strip, a magnetizable member attached to and continuing beyond one end of said strip and deformed to include as an armature a U portion, a permanent magnet adjacent to and cooperating with i said U portion, and a contact carried by said member, said member being apertnred between said contact and said strip.

4. In a thermostat, a fixed support, a first U member secured to said support, a second U member hinged on said first member intermediate the ends thereof and interengaging said first member, a spring between said U members at one end thereof urging said members to rotate away from each other about said pin, a binietal strip secured to said second U member at one end thereof, a nut fixed in position relative to said support, and a screw extending through said nut and bearing on said second U member to overcome the urge of said spring to move said members together.

5. In a thermostat, a bimetal strip, a. contact, a magnet, means for supporting said contact on said strip and for magnetization by said magnet to place a bias on said strip, said means consisting of a magnetizable member carrying said contact and deformed adjacent one end to provide a U section having a base cooperating as an armature with said magnet, said member being apertured between said contact and the other end of said member to reduce the mass of said member to prevent substantially contact heat irom affecting said bimetal strip, and means for attaching the other end of said member to said bimetal strip as a continuation of said strip.

5. In a thermostat, a. bimetal strip, a contact, a magnet, means for supporting said contact on said strip and for magnetization by said magnet to place a bias on said strip, said means consisting of a magnetizable member carrying said contact and deformed adjacent one end to provide a U section having a base cooperating as an armature with said magnet, and means between said contact and said strip for substantially isolating thermally from said strip that portion of said member adjacent to said con tact, and means for attaching said member to said bimetal strip as a continuation of said strip.

WILLIAMA. RAY. 

